In certain communication networks, certain communication nodes in the network are not easily accessible for repairs in the event that equipment on the communication node experiences a failure. For example, communication nodes located in space are practically inaccessible and, as such, that failed equipment cannot be repaired. To prevent the failures from affecting the operation of the communication node, the communication equipment on the communication node includes standby equipment that increases the redundancy of any communication paths through the communication equipment. To control which communication paths are used through the communication equipment, a switch network is used to switch a communication path from failed equipment to standby equipment.
In at least one example, low noise amplifiers are prone to failures. Thus, a communication node will include a number of spare amplifiers. For example, at any given time, the communication node may use at most M amplifiers. The communication equipment may include N amplifiers such that when any of the M amplifiers experiences a failure, the switch network switches the communication path through one of the N amplifiers that is not currently active and switches the communication path away from the amplifier that failed. This redundant configuration of amplifiers and switch networks may be referred to as N for M redundancy.
In certain implementations, a switch network can be implemented using a network of switching ferrite circulators. One configuration of ferrite circulators that offers N for M redundancy for connecting N input ports to M output ports is known as order constrained networks. An order constrained network of circulators allows that any M of the N input ports can be connected to the M output ports. However, order constrained networks can be complex, such that switching networks have a different design for different combinations of N and M. Thus, the order constrained network generally fails to provide the opportunity to reuse previously designed switch networks that implement ferrite circulators.
Further, certain implementations of switch networks are subject to further constraints. For example, a system that includes low noise amplifiers and switch networks may provide sufficient redundancy to handle the failure of at least three low noise amplifiers. Also, a system may be constrained such that upon experiencing the first failure of a low noise amplifier, the system is able to switch a communication path from an input through the switch network without affecting other communication paths through the switch network.